political unrest, perhaps leading to the violent overthrow of existing governments, becomes almost inevitable" (17, p. 26; see also 18). Earlier writers saw population growth as a condition for national power; now many demographers see population growth as a cause of international conflict. Mauser has presented a modern version of the lebensraum argument in his article "The Demographic Dimensions of World Politics." . . . the larger of these nations are not apt to remain hungry and frustrated without noting the relatively sparsely settled areas in their vicinity. The nations in the Southeast Asian peninsula: Burma, Thailand, and the newly formed free countries of Indo-China . . . even parts of thinly settled Africa may be subject to the aggressive action of the larger and hungrier nations as feelings of population pressure mount. Moreover, Communist China, the largest nation in the world by far, faced with . . . already heavy burdens . . . may not confine her attention only to the smaller nations within her reach. (19) The same argument is presented by Dorn in his report to the American Assembly (17, p. 16; sec also 20, 21, 22, 23), and it is further elaborated by Thompson in his widely circulating textbook on population (24, p. 503). Since no one has demonstrated a linkage between population density and aggressive behavior in international politics, some demographers have turned to an elusive psychological concept of "felt" population pressure. According to Thompson, population pressure includes "the relative pressure of population . . . defined as the degree of deprivation 'felt' by a people as it comes to know of the mcagerncss of its manner of living as compared with that enjoyed by other peoples. . . ." This notion permits the analyst to explain away the fuel that some aggressive countries have had lower population densities than the countries they attacked. Thompson proceeds to do just that by arguing that this feeling of population pressure was exploited by the leaders of Japan, Italy, and Germany in the 1930's and that similar feelings might be emerging in many developing countries.* In many instances, of course, attitudes and feelings about demographic changes have important effects on political behavior. This subject is later discussed in detail. However, a relation between population density and aggressive international behavior, explained by "felt" pressures, has not been proven nor disproven. If density is high and Ihu country is aggressive, population is called an explanatory variable; if density in the aggressive country is lower than in the country under attack, the analyst can point to "felt" pressure. *Sec (24). For earlier statements on "felt" population pressures, see (25, 26). Fora critique of Japanese efforts to claim population pressures as a factor in her military expansion, see (27). For an application of the concept to postwar Europe, sec (28, p. 253) in which Hol'stee defines population pressure as the "social tension originating from an "absolute or relative disproportion between population and available resources," a definition which led him to conclude in 1950 that population pressures in western i.-.irMm' in flin vizirs ahead could lead to "internal unrest."